Partial-filled baffle

ABSTRACT

A baffle for sealing a vehicle structure, comprising a carrier with an interior body portion characterized by a plurality of spaced-apart members, providing voids, and an expandable material, that may also have openings, disposed on the carrier which, upon expansion, fills a vehicle cavity and covers the interior body portion and each of the voids.

TECHNICAL FIELD

The present invention relates generally to a baffling and/or sealingmember that includes an expandable material and a carrier with voids andspaced-apart members formed of varying materials to reduce weightmaterial, and cost, and to improve sound attenuation characteristics.

BACKGROUND

The transportation industry continues to require methods of baffling andsealing that provide improved sound attenuation and also reduced weightand at a reduced cost. Often, when attempting to reduce the weight of apart providing baffling and/or sealing, the lightweight nature of thesupport material fails to provide the desired sound attenuation and/orsealing capabilities. Thus, reduced functionality often accompanieslightweight sealing and baffling mechanisms. Traditionally, a baffleincluding a full coverage open cell foam and a correspondingly shapedcarrier to support the foam provide an improved acoustic seal. However,the full coverage nature of such parts make them heavy and moreexpensive and may be met with assembly issues. It would therefore bedesirable to form a carrier and an associated foam that is not a fullcoverage device and yet provides improved acoustic and sealingcapabilities comparable to those of full coverage devices.

There is thus a need in the art of sealing for low weight sealing andbaffling assemblies that provide improved sealing and sound attenuationcharacteristics and are easily assembled while minimizing weight,material, and cost.

SUMMARY OF THE INVENTION

The present invention meets the aforementioned needs by providing bafflecomprising a carrier having an interior body portion with a plurality ofspaced apart members providing voids and a peripheral rim substantiallysurrounding the interior body portion. The device further it a thermallyexpandable sealing material disposed on the carrier in an amount and ofa material sufficient for thermally expanding to fill a vehicle cavityand cover the interior body portion and each of the voids.

The expandable material may be a material that is elastically deformablewithout rupture for forming a mechanical interconnection with a wall ofa cavity of a vehicle. The carrier may be a continuous surface that issubstantially free of protuberances. The expandable material may beattached to a face of the carrier. The end of the carrier and end of theexpandable material may not be co-extensive. The expandable material mayextend laterally to a portion short of a terminating edge of thecarrier. The expandable material may extend to a location that is atleast 1 mm from a terminating edge of the carrier. The baffle mayinclude a fastener formed as a nylon clip integrally formed with thecarrier. The baffle may be formed in a two step molding process in arotary mold. The baffle may be formed by a die-cutting process. Thebaffle may be formed by processing steps that are free of anydie-cutting process. An edge of the carrier may be formed surroundingeach void and the expandable material located about the voids is notco-extensive with the edge of the carrier surrounding each void. Theexpandable material may be co-extensive with the peripheral rim of thecarrier. The carrier and expandable material may be formed to eachinclude the same number of voids. The carrier and expandable materialmay be formed to include differing numbers of voids. The carrier may beformed with at least four voids.

The teachings herein further contemplate a method for forming thebaffles described herein comprising die cutting the carrier to form thevoids in the carrier and die cutting the expandable material to form thevoids in the expandable material so that the voids in the carriermaterial and the voids in the expandable material are located incorresponding locations with one another. The method may further includea step of locating the expandable material in direct planar contact withthe carrier so that the voids in the expandable material are in anoverlying relationship with the voids of the carrier. The method mayinclude a step of locating the baffle within a vehicle cavity. Themethod may include a step of exposing the expandable material to heat sothat the expandable material expands.

The invention herein contemplates a baffle for the sealing of cavitieswith a carrier having an interior body portion with a plurality ofspaced-apart members providing voids and one or more expendable sealingmaterials.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top down view of an illustrative example of the bafflestructure of the present invention.

FIG. 2 shows a side profile view of the baffle structure of FIG. 1.

FIG. 3 shows a cross-sectional view of the baffle structure of FIG. 1 atline A.

DETAILED DESCRIPTION

The explanations and illustrations presented herein are intended toacquaint others skilled in the art with the invention, its principles,and its practice application. Those skilled in the art may adapt andapply the invention in its numerous forms, as may be best suited to therequirements of a particular use. Accordingly, the specific embodimentsof the present invention as set forth are not intended as beingexhaustive or limiting of the teachings. The scope of the teachingsshould, therefore, be determined not with reference to the abovedescription, but should instead be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. The disclosures of all articles and references,including patent applications and publications, are incorporated byreference for all purposes. Other combinations are also possible as willbe gleaned from the following claims, which are also hereby incorporatedby reference into this written description.

This application is related to and claims the benefit of the prioritydate of U.S. Provisional Application Ser. No. 61/657,262, filed on Jun.8, 2012. The entirety of that application is hereby incorporated byreference for all purposes.

The present invention allows for improved baffling and sealing of acavity using substantially less material than a traditional baffle byproviding voids in one or more of the carrier and the expandablematerial. The baffle disclosed herein may include one or more sealingmaterials in addition to the carrier and expandable material, which mayor may not also include voids. The voids in the expandable material, ifpresent, may be formed so that they correspond in size and location withthe voids of the carrier. During expansion, the one or more expandablematerials may expand in one or more directions to substantially coverthe voids in the carrier.

The resulting baffle surprisingly provides sufficient sealing comparableto that of baffles including a full coverage carrier while using only apartial coverage carrier. Thus, formation of a baffle in accordance withthe present teachings surprisingly includes less carrier materials andexpandable materials, but provides a sealing device having full coverageof expandable material, partial coverage of carrier material and yetsufficient sound attenuation and sealing. However, despite existence ofthe voids in the carrier, the location of the spaced apart members ofthe carrier must provide sufficient support for the expandable material.As such, the distance between adjacent spaced apart member of thecarrier must not be so large that the expandable material either pre orpost expansion is likely to sag within the voids.

The size of the baffle may depend upon the size of the cavity in whichthe baffle located. The baffle, comprising the carrier and expandablematerial by virtue of the voids formed therein, is contemplated to coverno more than 80%, no more than 70%, no more than 60%, or even no morethan 50% of a cross section of the cavity, prior to expansion of theexpandable material. The voids formed in the baffle, thus, may representat least 20%, at least 30%, at least 40%, or even at least 50% of thecavity prior to expansion of the expandable material. The thickness ofthe baffle may be at least about 0.1 mm. The thickness of the baffle maybe less than about 10 mm. The thickness of the carrier and expandablematerial may be from about 0.5 mm to about 6 mm. The thickness of theexpandable material may be at least about 0.01 mm. The thickness of theexpandable material may be less than about 8 mm. The thickness of theexpandable material may be from about 0.2 mm to about 5 mm.

The adjacent spaced apart members of the carrier may be arranged so thatthe distance between adjacent members is equal. The adjacent spacedapart members of the carrier may be arranged so that the distancebetween adjacent members is not equal. The spaced apart members may bearranged substantially parallel to one another. The spaced apart membersmay be arranged substantially perpendicular to one another. The spacedapart members may form a grid configuration. The distance betweenadjacent spaced apart members may be at least about 0.25 mm. Thedistance between adjacent spaced apart members may be at least out 0.5mm. The distance between adjacent spaced apart members may be at leastabout 1.0 mm. The distance between adjacent spaced apart members may beat least about 3.0 mm.

The size and shape of the voids or openings formed in the carriermaterial may vary or may be substantially similar. The voids at theirlargest diameter may be at least about 1 mm, at least about 2 mm, oreven at least about 4 mm. The voids are their smallest diameter may beat least about 0.05 mm, at least about 0.1 mm or even at least about 0.2mm. The voids may be substantially rectangular in shape, substantiallytriangular in shape, or substantially rounded in shape. The shape, size,and number of the voids may vary depending upon the size of the baffle.For example, a smaller baffle (e.g., a baffle having a largest diameterof 2 mm or less) may include three voids or less, whereas a largerbaffle (e.g., a baffle having a largest diameter of at least about 10mm), may have 4 voids, 6 voids, 8 voids 10, voids or more.

The carrier may comprise a substantially planar polymeric substrate. Thecarrier may include a variety of materials such as polymers, elastomers,fibrous materials (e.g., cloth or woven materials), thermoplastics,plastics, nylon, and combinations thereof. The carrier may be injectionmolded in a multi-shot injection molding process. The carrier may bedie-cut. The carrier may also comprise a substantially planar metallicsubstrate such as steel. The surface of the carrier may be continuousand substantially free of protuberances.

The expandable material may be attached to a face of the carrier. It iscontemplated that the end of the expandable material and the end of thecarrier may or may not be co-extensive. The end of the carrier may beany location at which the carrier material does not extend further. Thusthe end of the carrier may be an end located adjacent the peripheraledge or an end located adjacent a void. It is thus contemplated that theend of the expandable material and the end of the carrier may beco-extensive at one or more ends of the carrier and may not beco-extensive at one or more ends of the carrier. It is furthercontemplated that the expandable material may extend laterally to aposition short of a terminating edge of the carrier or may extend to aposition that is equal to the extension of the terminating edge of thecarrier. Again, a terminating edge may be any carrier edge where thecarrier material does not extend further. The material may extend to alocation that is at least 1 mm from a terminating edge of the carrier.The material may extend to a location that is at least 0.5 mm from aterminating edge of the carrier. The material may extend to a locationthat is at least 0.25 mm from a terminating edge of the carrier.

The expandable material may also include one or more openings (e.g.,voids), as shown for example in FIGS. 1 and 3, and the voids may bepresent so as to reduce the amount of material required to effectivelyseal a cavity, thereby reducing the weight end cost of the baffle.Further, the presence of less than full coverage expandable material mayresult in more uniform expansion and coverage of the baffle uponexpansion of the expandable material. The expandable material may expandto fill the vehicle cavity and cover the interior body portion and eachof the voids in the carrier. The baffle may include edges, slots, orattachments that guide the expansion of the expandable sealing materialand thus prevent the expandable material from covering the one or moreopenings.

After placement of the baffle into a cavity, the expandable sealingmaterials may expand according to a predetermined set of conditions. Forexample, exposure to certain levels of heat may cause the expandablematerials to expand. The volumetric expansion of the expandablematerials may vary depending upon the sealing and/or baffling needs of aparticular cavity. The expandable material may expand to fill thevehicle cavity and cover the voids in the interior body portion of thecarrier. The expandable material may expand at least about 100%. Theexpandable material may expand less than about 2000%. The expandablematerial may expand at least about 500%, at least about 1000%, or more.The expandable material may expand less than about 1000% or even lessthan about 500%.

The expandable sealing materials may be generally dry to the touch ortacky and may be shaped in any form of desired pattern, placement, orthickness, but is preferably of substantially uniform thickness. Thoughother heat-activated materials are possible for the expandable sealingmaterials, a preferred heat activated material is an expandable polymeror plastic, and preferably one that is foamable. The expandable sealingmaterials may be relatively high expansion foams having a polymericformulation that includes one or more of an epoxy resin, an acetate(e.g. ethylene vinyl acetate), a thermoplastic polyether, an acrylateand/or a methacrylate (e.g., a copolymer of butyl acrylate and methylacrylate), an epoxy/elastomer adduct, and one or more fillers (e.g., aclay filler, and/or a nanoparticle-containing filler). Preferredthermally expandable materials are disclosed in U.S. Pat. Nos.7,313,866; 7,125,461; and 7,199,165 incorporated by reference herein forall purposes. For example, and without limitation, the foam may also bean EVA/rubber based material, including an ethylene copolymer orterpolymer that may possess an alpha-olefin. As a copolymer orterpolymer, the polymer is composed of two or three different monomers,i.e., small molecules with high chemical reactivity that are capable oflinking up with similar molecules Suitable expandable materials includethose available from L & L Products, Inc. under the designations L7220,L2821, L1066, L205, L2010, L2105, L2108A, L2806, L2811, L4200, L4141,L4161, L4315, L5510, L5520, L5540, L5600, L5601, L7102, and L7104. Theexpandable materials may be die cut extruded sheets of material. Theymay be co-injection molded with the carrier in a multi-shot injectionmolding process.

A number of baffling or sealing foams may also be used for theexpandable sealing materials. A typical foam includes a polymeric basematerial, such as one or more ethylene-based polymers which, whencompounded with appropriate ingredients (typically a blowing and curingagent), will expand and cure in a reliable and predictable manner uponthe application of heat or the occurrence of a particular condition.From a chemical standpoint for a thermally-activated material, the foamis usually initially processed as a flowable material before curing, andupon curing, the material will typically cross-link making the materialincapable of further flow.

The expandable material can be formed of other materials provided thatthe material selected is heat-activated or otherwise activated by anambient condition (e.g. moisture, pressure, time or the like) and curesunder appropriate conditions for the selected application. One suchmaterial is the epoxy based resin disclosed in U.S. Pat. No. 6,131,897,the teachings of which are incorporated herein by reference. Some otherpossible materials include, but are not limited to, polyolefinmaterials, copolymers and terpolymers with at least one monomer type analpha-olefin, phenol/formaldehyde materials, phenoxy materials, andpolyurethane materials with high glass transition temperatures.Additional materials may also be used such as those disclosed in U.S.Pat. Nos. 5,768,719; 5,755,486; 5,575,626; and 5,932,680, incorporatedby reference herein for all purposes.

In applications where the expandable material is a heat activatedmaterial, an important consideration involved with the selection andformulation of the material temperature at which a material cures and,if expandable, the temperature of expansion. Typically, the materialbecomes reactive (cures, expands or both) at higher processingtemperatures, such as those encountered in an automobile assembly plant,when the material is processed along with the automobile structures atelevated temperatures or at higher applied energy levels, e.g., duringcoating (e.g., e-coat, paint or clearcoat) curing steps. Whiletemperatures encountered in an automobile assembly operation may be inthe range of about 148.89° C. to 204.44° C. (about 300° F. to 400° F.)for body shop applications (e.g., e-coat) and, for paint shopapplications are commonly about 93.33° C. (about 200° F.) or slightlyhigher (e.g., 120° C.-150° C.).

The expandable material may be mechanically attached to the carrier. Theexpandable sealing material may expand to contact one or more cavitywalls to seal the cavity and may be bonded to the carrier over itsentire surface or a face of the carrier or may be locally bonded to thecarrier at selected locations (e.g., using a tacking type attachment).

The baffle may include a fastener such as a tree-fastener or a threadedscrew fastener. Alternatively, the baffle may be substantially free ofany fastener. The fastener may also be provided in a variety of shapesand in a variety of configurations so long as it can secure the sealingdevice to a cavity. One example of a suitable fastener is disclosed inU.S. Publication No. 2010/0021267 incorporated by reference herein forall purposes. The fastener may be capable of securing multiple layers ortypes of materials to a structure. Examples of suitable fastenersinclude mechanical fasteners, clips, tabs, press-fits, snap-fits,screws, hooks, combinations thereof or the like. Furthermore, it iscontemplated that the one or more fasteners may be formed integral of asingular material with the carrier, such as a nylon clip integrallyformed with the carrier, or material of the sealing device, or may beformed of a different material and may be removably attached to thecarrier. The fastener may be provided as a magnetic mate or an adhesivematerial that can attach (e.g., adhere or magnetically secure) thesealing device to a cavity. In such an embodiment, the magnetic materialor the adhesive material may be interspersed within the first sealingmaterial or the second sealing material. Alternatively, the magneticmaterial or the adhesive material may be disposed upon the first sealingmaterial and/or the second sealing material or may be otherwiseconnected to the first sealing material the carrier and/or the secondsealing material.

The baffle may include fastening devices for attaching the expandablematerial to the carrier. Such devices may be integrally formed with thecarrier or attached separately. Such devices may include slots, troughs,extension members, or any other shape that may be formed in or attachedto the carrier for receiving or connecting to the expandable material.

FIG. 1 shows a baffle structure 10 including a carrier 12. The carrier12 may include a plurality of spaced apart members 22 to form voids 18.From a side profile view as shown in FIG. 2, the carrier 12 and anexpandable material 14 lie in direct planar contact with one anotheralong at least the peripheral rim 16 of the carrier 12. As shown inFIGS. 1 and 3, the expandable material 14 may include one or moreopenings (e.g., voids) 20. A shown in FIG. 3, the expandable material 14may extend only over a portion of the carder 12. The voids 18 formed inthe carrier and the voids 20 formed in the expandable may be formed sothat they correspond with one another in location, size and shape asshown in FIGS. 1 and 3.

The baffle of the present invention may be installed into an automotivevehicle although it may be employed for other articles of manufacturesuch as boats, buildings, furniture, storage containers or the like. Thebaffle may be used to seal and/or baffle a variety of components of anautomotive vehicle including, without limitation, body components (e.g.,panels), frame components (e.g., hydroformed tubes), pillar structures(e.g., A, B, C or D-pillars), bumpers, roofs, bulkheads, instrumentpanels, wheel wells, floor pans, door beams, hem flanges, vehiclebeltline applications, doors, door sills, rockers, decklids, hoods orthe like of the automotive vehicle.

Formation of the materials of the present invention may include avariety of processing steps depending on the desired configuration ofthe materials. The baffle may be formed using a two step molding processin a rotary mold and/or a die cutting process. The processing steps mayalso be free of any die-cutting process. One or more of the carrier andthe expandable material may be formed in an injection molding processwhich may be a multi-snot injection molding process. Additionalprocessing and formation steps may not be required. The formation andprocessing may thus be free of any extrusion process.

Any numerical values recited herein include all values from the lowervalue to the upper value in increments of one unit provided that thereis a separation of at least 2 units between any lower value and anyhigher value. As an example, if it is stated that the amount of acomponent or a value of a process variable such as, for example,temperature, pressure, time and the like is, for example, from 1 to 90,preferably from 20 to 80, more preferably from 30 to 70, it is intendedthat values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. areexpressly enumerated in this specification. For values which are lessthan one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 asappropriate. These are only examples of what is specifically intendedand all possible combinations of numerical values between the lowestvalue and the highest value enumerated are to be considered to beexpressly stated in this application in a similar manner. As can beseen, the teaching of amounts expressed as “parts by weight” herein alsocontemplates the same ranges expressed in terms of percent by weight.Thus, an expression in the Detailed Description of the Invention of arange in terms of at “‘x’ parts by weight of the resulting polymericblend composition” also contemplates a teaching of ranges of samerecited amount of “x” in percent by weight of the resulting polymericblend composition.

Unless otherwise stated, all ranges include both endpoints and allnumbers between the endpoints. The use of “about” or “approximately” inconnection with a range applies to both ends of the range. Thus, “about20 to 30” is intended to cover “about 20 to about 30”, inclusive of atleast the specified endpoints.

The disclosures of all articles and references, including patentapplications and publications, are incorporated by reference for allpurposes. The term “consisting essentially of” to describe a combinationshall include the elements, ingredients, components or steps identified,and such other elements ingredients, components or steps that do notmaterially affect the basic and novel characteristics of thecombination. The use of the terms “comprising” or “including” todescribe combinations of elements, ingredients, components or stepsherein also contemplates embodiments that consist essentially of theelements, ingredients, components or steps. By use of the term “may”herein, it is intended that any described attributes that “may” beincluded are optional.

Plural elements, ingredients, components or steps can be provided by asingle integrated element, ingredient, component or step. Alternatively,a single integrated element, ingredient, component or step might bedivided into separate plural elements, ingredients, components or steps.The disclosure of “a” or “one” to describe an element. ingredient,component or step is not intended to foreclose additional elements,ingredients, components or steps.

It is understood that the above description is intended to beillustrative and not restrictive. Many embodiments as well as manyapplications besides the examples provided will be apparent to those ofskill in the art upon reading the above description. The scope of theinvention should, therefore, be determined not with reference to theabove description, but should instead be determined with reference tothe appended claims, along with the full scope of equivalents to whichsuch claims are entitled. The disclosures of all articles andreferences, including patent applications and publications, areincorporated by reference for all purposes. The omission in thefollowing claims of any aspect of subject matter that is disclosedherein is not a disclaimer of such subject matter, nor should it beregarded that the inventors did not consider such subject matter to bepart of the disclosed inventive subject matter.

1. A baffle comprising: a carrier having a peripheral rim substantiallysurrounding an interior body portion, the interior body portion beingcharacterized by a plurality of spaced-apart members providing voids; anexpandable material disposed on the carrier in an amount and of amaterial sufficient for thermally expanding to fill a vehicle cavity andcover the interior body portion and each of the voids.
 2. The baffle ofclaim 1, wherein the carrier is a continuous surface that issubstantially free of protuberances.
 3. The baffle of claim 1, whereinthe expandable material is attached to a face of the carrier.
 4. Thebaffle of claim 1, wherein the end of the carrier and end of theexpandable material are not co-extensive
 5. The baffle of claim 1,wherein the expandable material extends laterally to a portion short ofa terminating edge of the carrier.
 6. The baffle of claim 1, wherein theexpandable material extends to a location that is at least 1 mm from aterminating edge of the carrier.
 7. The baffle of claim 1, wherein thebaffle includes a fastener formed as nylon clip integrally formed withthe carrier.
 8. The baffle of claim 1, wherein the baffle is formed in atwo step molding process in a rotary mold.
 9. The baffle of claim 1,wherein the baffle is formed by a die-cutting process.
 10. The baffle ofclaim 1, wherein the baffle is formed by processing steps that are freeof any die-cutting process.
 11. The baffle of claim 1, wherein thecarrier includes an integrally formed or separately formed tab,adhesive, post, pow-tab, or any combination thereof for attachment ofthe expandable material to the carrier.
 12. The baffle of claim 1,wherein the carrier or the expandable material, or both include anintegrally formed or separately formed tab, adhesive, post, pow-tab, orany combination thereof for attachment of the baffle to a wall of thevehicle cavity.
 13. The baffle of claim wherein an edge of the carrieris formed surrounding each void and the expandable material locatedabout the voids is not co-extensive with the edge of the carriersurrounding each void.
 14. The baffle of claim 1, wherein the expandablematerial co-extensive with the peripheral rim of the carrier.
 15. Thebaffle of claim 1, wherein the carrier and expandable material areformed to each include the same number of voids.
 16. The baffle of claim1, wherein the carrier and expandable material are formed to includediffering numbers of voids.
 17. The baffle of claim 1, wherein thecarrier is formed with at least four voids.
 18. A method for forming thebaffle of claim 1 comprising: die cutting the carrier to form the voidsin the carrier; die cutting the expandable material to form the voids inthe expandable material so that the voids in the carrier material andthe voids in the expandable material are located in correspondinglocations with one another; locating the expandable material in directplanar contact with the carrier so that the voids in the expandablematerial are in an overlying relationship with the voids of the carrier.19. The method of claim 18 including locating the baffle within avehicle cavity.
 20. The method of claim 18 including exposing theexpandable material to heat so that the expandable material expands.